Window AC Unit as a glycol chiller?

[mpcluever]

I've seen some of these on the internet, but never really any details about how they were built. Anyone have any details on using an AC unit to chill a glycol bath?

 

[Jipper]

I have one of these at home, and it works really well. I use a single stage un-wired Ranco controller, and you'll need to bypass the temperature sensor on your AC unit so that it knows to turn on/off when the Ranco's probe tells it to. You'll submerge the cooling apparatus (looks like a car's radiator) into the glycol bath which is what will keep it cool. I use a March Pump to pump from the reservoir to my glycol manifold, and have the return coming in through the top of the cooler this is built on.

I didn't do the electrical work myself - I have an electrician / HVAC friend that helped me with that. All AC units should have a wiring diagram inside the shell (sometimes on the outside also), and the Ranco will come with one as well.

From my understanding it is an easier conversion with a non-digital AC unit, but that's just what my friend was telling me. My unit is 5000 BTU and can cold crash two 14 gallon conicals to ~45F in a 100F garage. I can take pictures of it if you'd like to see - just let me know. Sorry I don't know what wires go where, but that will also depend on the AC unit you end up going with...

Cheers!

 

[iwashappy]

Would be awesome to see some pix. Was just thinking about doing this myself! I'm especially interested to see how you built the glycol reservoir.

 

[starman]

I'd love to see it too. A 5000 BTU AC unit as a central chiller should be able to cool a whole array of brew in properly sealed and insulated compartments. A 4-6 keg serving unit, a couple lager boxes, and a whole bunch of ales would probably be less than 25% of cooling capacity.

 

[mpcluever]

FYI, I found an entire write up on this in one of the special BYO DIY Projects editions. Haven't started it yet and the article, was kind of vague regarding the actual build of the AC unit glycol system, but looks easy enough.

 

[armageddon]

Jipper,

I'm very interested in seeing pictures of your setup.

-Erik

 

[Jipper]

Alright - so here are a few pictures of the AC glycol unit. I have it set to 30F with a 4 degree differential. The reservoir is a white cooler (72 quart I believe). We cut half of the top off and screwed the AC unit on the right side. The other half had 4 cup holders, which we drilled out and installed the return line in, as well as the temperature probe. I would recommend a thermowell, however do not currently use one and things seem to be working alright. The cooler came equipped with a spigot/water drain on the right, which I removed and installed a weldless fitting in its place. We use a H315HF March Pump (their part number is 815 I believe) to move the glycol throughout the manifold, which you can see is mounted above the glycol unit. When building the manifold we created 7 different outlets/inlets, to allow for future growth if wanted/needed. We currently use it connected to two 14 gallon conicals and two cellar kegs that are used for secondary/conditioning. We have had all four of those going before and the 5000BTU unit was able to keep them all at temperature. We've also put lagers into both of the conicals at the same time, and both were able to hold 49F in ~80F ambient temperatures. The manifold has ball valves on the return lines, and solenoid valves on the outlet. The solenoids are plugged into the "Cooling" outlet of the ranco controller, and therefore will only turn on and allow glycol through the coils when the temperature inside the conical is above the set point. We currently have a Zinfandel in one of our cellar kegs (we use them for beer, wine, and mead), and it's cold crashing, currently at 44F in the picture. The garage was around 88F when the picture was taken.

Let me know if you have any questions. Again - I'm unable to help with the re-wiring of the ranco and AC unit, but almost anything else I'd be able to help with. Cheers!

 

[audger]

Would be awesome to see some pix. Was just thinking about doing this myself! I'm especially interested to see how you built the glycol reservoir.

i was playing with the idea a while ago. this is the first generation of my glycol chiller- its very cobbled together, and there are a lot of things i plan to improve, but here it is...

8000 BTU compressor, 12 gallon box i buit out of wood and fiberglassed around the inside of it. controlled by an arduino and some relays, with a 120v surflow diaphragm pump. it powers the keg chiller right below it, and the tap system up in the kitchen on the first floor (its in the basement). its about a 35 foot run. i have a third solenoid on the chiller manifold that will eventually go to a fermentation chamber whenever i get around to it. enjoy.
(sorry i dont have any great head-on pictures of the whole thing, its tucked under the basement stairs)

 

[starman]

Thanks to you both for the photos. So it looks like you both were able to get the AC (evap) cooling coil to just sit in the glycol resevoir below? Did you have to suction and refill the system to reconfigure the ac lines or was there enough play to just suspend it into the pool?

 

[wyzazz]

Very interesting! Anyone willing to make a little generic diagram of the parts of the AC Unit, pumps, etc?

 

[Zed805]

Try using a chest freezer to chill your glycol. Simply fill the chest freezer with a mixture of water and glycol (i.e. the chest freezer IS the reservoir and chiller), add a temperature controller to keep the freezer at or above 26 degrees F. Install an aquarium pump attached to a temperature controller for each fermentor/bright tank you have to recirculate the glycol. Costs about $300 to build, and all you have to do is drill the holes in the freezer for the glycol lines to exit/return. Very simple and easy.

I spoke with some glycol specialists. They informed me that a 500 gallon fermentor only has about 5 gallons of glycol in the jacket AND only needs about 10 gallons in reserve to keep the temperature at the required level. In other words, you wont need much glycol for a smaller scale operation.

On a side note, we all know the cheapest way to keep your fermentors at the appropriate temperature is to put them in a room with a window and buy a window A/C unit. Just keep the room at 64 degrees or so. Presto! $100 temperature controlled fermentation. No fuss, no muss!

 

[starman]

Try using a chest freezer to chill your glycol. Simply fill the chest freezer with a mixture of water and glycol (i.e. the chest freezer IS the reservoir and chiller), add a temperature controller to keep the freezer at or above 26 degrees F. Install an aquarium pump attached to a temperature controller for each fermentor/bright tank you have to recirculate the glycol. Costs about $300 to build, and all you have to do is drill the holes in the freezer for the glycol lines to exit/return. Very simple and easy.

I spoke with some glycol specialists. They informed me that a 500 gallon fermentor only has about 5 gallons of glycol in the jacket AND only needs about 10 gallons in reserve to keep the temperature at the required level. In other words, you wont need much glycol for a smaller scale operation.

On a side note, we all know the cheapest way to keep your fermentors at the appropriate temperature is to put them in a room with a window and buy a window A/C unit. Just keep the room at 64 degrees or so. Presto! $100 temperature controlled fermentation. No fuss, no muss!

The typical chest freezer doesn't kick out the same BTU/hour cooling that a window AC provides. A typical dorm fridge provides 100-150 BTU/H and a chest freezer probably isn't more than triple that. 5000 BTU/H AC are readily available which theoretically has the capacity to cool a 4-6 keg servery, several lagering chambers, and a huge reserve for 55-70 degree ale / cold grain storage chambers. All with the benefit of one central compressor which would be much cheaper than 4-5 chest freezers.

 

[hatrickwah]

Each A/C unit is going to be slightly different to wire but the basics are there on each. Took me a few trials confirm.
My setup... early in its life..

Its grown up since, but I don't have any recent pics, but at some point will post.
More details in my build thread.

 

[starman]

Each A/C unit is going to be slightly different to wire but the basics are there on each. Took me a few trials confirm.
My setup... early in its life..

Its grown up since, but I don't have any recent pics, but at some point will post.
More details in my build thread.

Very nice build & thread. I've briefly scanned the brewtroller site and it seemed like the fermtroller doesn't have as big a user base. Do you think the system has enough documentation that a person with really limited programming and almost no lv electronics experience could get it working?

It seems like up to 3-4 zones on stc-1000's is cost competitive with a brewtroller or arduino build but you give up the ability to have smart dynamic control like importing a beersmith fermentation profile.